In recent years, in a light emitting display device for mobile purposes, there is a strong demand for high resolution and low power consumption. Display devices which use a liquid crystal display device (LCD) or organic light-emitting diode (OLED) such an organic EL display device or electronic paper etc are being adopted.
Among these, because an organic EL display device does not require a back light or polarizing plate which were necessary in liquid crystal devices, it is possible to form a display device just with a thin film. In addition, it is possible to realize a display device capable of bending (flexible). Furthermore, since these display devices do not use a glass substrate, they are display devices which are light and difficult to break. For these reasons, organic EL display devices are attracting a lot of attention. In addition, in an organic EL display device of a medium/small size, high definition and a narrow frame of a display part is required.
In order to achieve an organic EL display device with high definition, a device structure mounted with RGB pixels are being developed by combining white organic EL elements with color filters (CF) to achieve a “white+CF structure”. In addition, in order to achieve a narrow frame, it is necessary to reduce the area of the periphery region of the display device. In order to achieve this, it is necessary to narrow the width of a seal component arranged in the periphery region of a pixel and reduce the distance between the seal component and display region.
Here, a light emitting element such as an organic EL element arranged in each pixel of an organic EL display device is known to degrade when exposed to oxygen or water which decreases light emitting efficiency. In order to solve this problem for example, a display device is disclosed in the Japanese Laid Open Patent 2007-194184 in which a sealing structure with high air sealing properties is disclosed by bonding a substrate arranged with a light emitting element and an opposing substrate which faces the substrate using a glass frit.
However, in the “white+CF structure” described above, especially in the case where a color filter is arranged between two bonded substrates, the light element sometimes degrades due to degassing or dehydration from the color filter. In addition, when narrowing of the frame of the display device increases, the distance between the glass frit which fuses the two substrates and the display region arranged with the pixels is reduced. As a result, when fusing by local heating the glass frit using laser radiation etc, a part of the laser is irradiated on a pixel of the display region which causes degradation of the light emitting element. In addition, heat generated by local heating due to laser irradiation is transmitted to a light emitting element of a pixel arranged in the display region which sometimes leads to degradation of the light emitting element.